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Business-as-unusual: Exploring port stakeholders’ time tactics for mediating recent disruptions at the Port of Rotterdam
No full textSeaports function as infrastructural nodes at which the disparate rhythms of global logistical flows are synchronized toward just-in-time management. Port disruptions challenge this regular time regime. This article explores the role of infrastructures and time tactics in mediating port disruptions associated with the COVID-19 pandemic and the war in Ukraine. Building on three interrelated notions of time—infrastructural time regimes, infrastructural rhythms, and infrastructural time tactics—our analysis of stakeholder interviews revealed that to manage port disruptions, port stakeholders applied various time tactics to certain processes: activating or deactivating, prioritizing or downgrading, continuing or discontinuing, and increasing or decreasing. By employing these time tactics to maintain, adapt, and transform port rhythms in response to disruptions, port stakeholders attempted to resynchronize disrupted port rhythms into a different time regime. We demonstrate that this time regime is “hybrid,” as it comprises not only elements of just-in-time management but also elements of just-in-case management. This finding introduces a more nuanced understanding of the temporary hybridization of time regimes during periods of disruptions and highlights the role of infrastructures in mediating time
Contestations of Liberal Globalism and the Rise of the Retrograde Party
No full textThe crisis of the liberal order opened up space for ideas that only some years ago had appeared out of time. During globalization’s heyday, parties that called for a rollback of liberal globalism were either stuck in a marginal position or unable to implement fundamental reforms. This has changed as the main political approaches toward liberal globalism are now being publicly and electorally contested. We argue that this has triggered the rise of a phenomenon we refer to as retrogradism. This article applies the concept of retrogradism to the case of the German right-wing party Alternative für Deutschland (AfD). It argues that we may be witnessing the rise of a new type of political party that pursues a retrograde agenda. We suggest that the current debate on the AfD fails to take into account that its defining features may be its politics of time and its retrograde opposition to liberal globalism
Self-Driven Fluid Imbibition of Salt Solutions into Mesoporous Films
No full textFluid water imbibition into nanoscale porous materials is important in nature and technology and has
been shown to follow Lucas-Washburn behavior. Looking at drop imbibition into nanoscale porous films the
imbibition reaches a steady state governed by capillary imbibition and evaporation which is reflected in a constant
imbibition length. This imbibition length in a steady state depends on the porous structure as well as on the
material’s wettability and the fluid evaporation rate, for example. As the presence of salts affects these
parameters, the imbibition length is expected to be influenced by the solutes present in the drop. Here, we show
the influence of salt presence, salt concentration, and ion type on the fluid imbibition of an aqueous salt solution
into mesoporous silica films. We observe, that salts affect the Lucas-Washburn imbibition occurring directly after
drop positioning on mesoporous films. Interestingly, the presence of salts also causes a continuous increase of
the characteristic imbibition length at longer time scales preventing the formation of a steady state after the initial
Lucas-Washburn-like imbibition. We identified a self-amplified fluid pumping mechanism using mesoporous silica
films. We attribute this continuous fluid pumping and thus the continuous increase of the imbibition length to the
increasing osmotic pressure within mesoporous materials upon constant fluid flow and fluid evaporation.
Understanding aqueous salt solution imbibition into mesoporous films is an important aspect e.g. in the context
of material exchange between drops through mesoporous films
Shining New Light on the Mechanism of Selective Oxidation Catalysis Using Method Development in Transient Spectroscopy
No full textSelective oxidation reactions are some of the most important chemical processes, with enormous economic and environmental contributions. Controlling the selectivity remains the greatest challenge, owing to their complexity, with both parallel and consecutive reaction pathways leading to by-products. Their mode of operation over supported and bulk oxide catalysts has been the subject of debate for decades, largely influenced by phenomenological principles. Recently, direct evidence from transient spectroscopy has provided insight into the dynamical nature of selective oxidation catalysts as well as the actively participating surface species and sites of the catalysts, while highlighting important functions of the supporting structure. This perspective presents the implications of these findings for a scientific understanding of the characteristics of selective oxidation reactions as a basis for rational catalyst design. First, the potential of the transient spectroscopic approach is illustrated based on the available literature on selective oxidation reactions. When moving from supported catalysts to bulk oxide systems with their increased level of structural complexity, additional challenges concerning the determination of structure–performance relationships emerge, but these may be tackled successfully in the future in view of current method development
Simultaneous Bacteria Sensing and On-demand Antimicrobial Peptide Release
No full textA material able to simultaneously sense a bacterial presence and to on-demand release antimicrobial peptides (AMP) in a tunable amount was developed. Simultaneous sensing and release were achieved by the combination of a bacteria-sensing hydrogel with antimicrobial peptide-carrying mesoporous silica particles or coatings. The mesoporous silica with a mesopore diameter of 22 nm was functionalized with a covalently grafted green light-sensitive linker to which antimicrobial peptides were covalently attached. The gelatin-based hydrogel, which contains C14R functionalized mesoporous silica particles, is designed to respond to bacteria presence as it may occur e.g. in a wound's microbiological environment.
In the presence of bacteria and 0.1 % trypsin, a protease enzyme simulating bacterial presence, the hydrogel, deposited in a donut shape, undergoes a shape loss as the bacteria cleave cross-linking bonds within the hydrogel. When observing hydrogel shape loss after 2 hours as a readout of a bacterial infection subsequent irradiation triggers the release of antimicrobial peptides on demand with adjustable concentration-time profiles. The sensing and on-demand release are integrated into commercially available wound dressing fabrics demonstrating an application proof-of-concept. Characterization using ATR-IR spectroscopy, TGA, and BCA validate the successful fabrication and release. The H1.6P composite released antimicrobial agents, reaching concentrations of up to 298 μg/mL at pH 7.4 from a 300 μL sample. The efficacy of the released C14R against E. coli BL21(DE3) is illustrated. Overall, the multifunctionality of this approach presents a promising step towards on-demand wound care and thus for reducing side effects and antibiotic resistance
PEO-b-PNBA in-situ functionalized mesoporous silica films and their light- and pH-controlled ionic mesopore accessibility
No full textMultistimuli-responsive, in-situ functionalized mesoporous silica films were fabricated by evaporation-induced self-assembly through physical entrapment of the functional template poly(ethylene oxide)-b-poly(2-nitrobenzyl acrylate) (PEO-b-PNBA). The light-cleavable and pH-responsive block copolymer PEO-b-PNBA simultaneously serves as structure-directing agent and for in-situ polymer functionalization of the generated mesopore space. The use of different PEO-b-PNBA compositions results in highly filled hybrid mesoporous silica films with different pore sizes, porosity, and polymer chain sequence within the mesopores. Based on these structural variations and the polymer chain sequence the ionic permselectivity of the silica-polymer hybrid thin films is adjusted. The side chains of the template PNBA block can be deprotected upon irradiation, hereby releasing pH-responsive carboxylic acid groups. The irradiation energy and irradiation time-dependent deprotection allows gradually controlled charge regulation in mesopores. This approach of in-situ functionalization using multistimuli-responsive PEO-b-PNBA block copolymers facilitates the fabrication of multi-responsive hybrid mesoporous silica films and bears high potential for the production of complex, hierarchical, multifunctional mesoporous materials. This fabrication method including direct functionalization of mesoporous structures is of high interest for many applications based on controlled molecular transport in nanoscale pores, such as sensing, separation, or catalysis
Correlating spatially resolved catalysis and Raman spectroscopy during CO oxidation over Cu/CeO₂ catalysts
No full textSpatially resolved analysis allows for the development of accurate structure–property correlations in regimes of high catalytic conversion. We report on the novel combination of a compact profile reactor with IR spectroscopy for spatially resolved gas-phase analysis and with Raman spectroscopy for spatially resolved structural analysis. The potential of this combined approach is illustrated for the CO oxidation over low-loaded Cu/CeO₂ catalysts at atmospheric pressure but the use of higher pressures is feasible. Spatially resolved operando Raman spectroscopy of Cu/CeO₂ at 150 °C reveals structural changes directly correlated with the catalytic conversion. With increasing conversion an increase in the consumption of surface lattice oxygen is observed which is accompanied by the formation of oxygen vacancies and ceria reduction. Our mechanistic findings demonstrate the participation of the ceria support in the CO oxidation over low-loaded Cu/CeO₂ catalysts at high conversions. The presented setup provides high versatility for spatially dependent mechanistic analysis of catalysts as a function of varying gas environments and their influence on the structural changes
Structure of the Dispase Autolysis-inducing Protein from Streptomyces mobaraensis and Glutamine Cross-linking Sites for Transglutaminase
Full text linkTransglutaminase from Streptomyces mobaraensis (MTG) is an important enzyme for cross-linking and modifying proteins. An intrinsic substrate of MTG is the dispase autolysis-inducing protein (DAIP). The amino acid sequence of DAIP contains 5 potential glutamines and 10 lysines for MTG-mediated cross-linking. The aim of the study was to determine the structure and glutamine cross-linking sites of the first physiological MTG substrate. A production procedure was established in Escherichia coli BL21 (DE3) to obtain high yields of recombinant DAIP. DAIP variants were prepared by replacing four of five glutamines for asparagines in various combinations via site-directed mutagenesis. Incorporation of biotin cadaverine revealed a preference of MTG for the DAIP glutamines in the order of Gln-39 ≫ Gln-298 > Gln-345 ∼ Gln-65 ≫ Gln-144. In the structure of DAIP the preferred glutamines do cluster at the top of the seven-bladed β-propeller. This suggests a targeted cross-linking of DAIP by MTG that may occur after self-assembly in the bacterial cell wall. Based on our biochemical and structural data of the first physiological MTG substrate, we further provide novel insight into determinants of MTG-mediated modification, specificity, and efficiency
Cascade enzymatic synthesis of a statin side chain precursor – the role of reaction engineering in process optimization
Full text linkStatins are an important class of drugs used to lower blood cholesterol levels and are often used to combat cardiovascular disease. In view of the importance of safe and reliable supply and production of statins in modern medicine and the global need for sustainable processes, various biocatalytic strategies for their synthesis have been investigated. In this work, a novel biocatalytic route to a statin side chain precursor was investigated in a one-pot cascade reaction starting from the protected alcohol N-(3-hydroxypropyl)-2-phenylacetamide, which is oxidized to the corresponding aldehyde in the first reaction step, and then reacts with two equivalents of acetaldehyde to form the final product N-(2-((2S,4S,6S)-4,6-dihydroxytetrahydro-2H-pyran-2-yl)ethyl)-2-phenylacetamide (phenylacetamide-lactol). To study this complex reaction, an enzyme reaction engineering approach was used, i.e. the kinetics of all reactions occurring in the cascade (including side reactions) were determined. The obtained kinetic model together with the simulations gave an insight into the system and indicated the best reactor mode for the studied reaction, which was fed-batch with acetaldehyde feed to minimize its negative effect on the enzyme activity during the reaction. The mathematical model of the process was developed and used to simulate different scenarios and to find the reaction conditions (enzyme and coenzyme concentration, substrate feed concentration and flow rate) at which the highest yield of phenylacetamide-lactol (75%) can be obtained. In the end, our goal was to show that this novel cascade route is an interesting alternative for the synthesis of the statin side chain precursor and that is why we also calculated an initial estimate of the potential value addition
Need a Good Book about Privacy? Evaluating Dictionary-Based Corpus Query for Detecting the Topic of Privacy in Literary Texts
Full text linkThis paper evaluates the usefulness of querying Vasalou et al.’s Privacy
Dictionary (2011), a dictionary of 600+ words and phrases, in 131 canonical
English-language novels from the long 19th century. We evaluate the word
frequencies compared with a classification of the novels based on scholarly
attention to the topic of privacy in each particular text. We report evidence of
low- to low/medium strength of correlation between 3 of the 8 categories of
the Privacy Dictionary and this classification. As a final step, by identifying the
novels in our corpus which score highest in relative word frequency in these 3
categories, we suggest novels which have not yet received scholarly study on
the topic of privacy but which may be promising for such studies. The highest
scoring novel by our method, Maria Edgeworth’s Castle Rackrent (1800), seems
indeed to be highly concerned with the topic of privacy, which is discussed in
its author’s preface and opening pages